Bombs have killed at least 15 people across Iraq on Thursday, including eight police officers and a soldier, in the latest strike against Iraqi security forces as US troops prepare to leave.

Gunmen attacked a police station in the town of Karmah, about 50 miles west of Baghdad. After exchanging gunfire with the policemen, the gunmen withdrew and a car bomb exploded near the police station, killing five of the police officers, Iraqi police and hospital officials said.

About 30 minutes later a parked car bomb exploded near a police checkpoint in a village outside of Fallujah, 40 miles west of Baghdad. Three policemen and one civilian were killed in the second attack, officials said.

Fallujah was the scene of fierce fighting between US troops and Sunni militants in 2004. The city has since revitalised, but bombings and attacks against Iraqi security forces who are seen as allied with the Shiite-led government are still common.

In the southern city of Basra, a suicide bomber blew up his vehicle near a Shiite mosque, said Ayad al-Emarah, press secretary for the Basra provincial governor. Four worshippers died and another 50 were injured, said hospital and morgue officials.

Such attacks, especially those involving a suicide bomber, are rare in Basra, which has seen increasing foreign investment and foreign visitors as Iraq tries to boost its oil exports.

Earlier in the day, a roadside bomb exploded near an Iraqi army checkpoint in eastern Mosul, police said. One soldier died in the afternoon blast in the city that was once an al Qaida hotbed.

Al Qaida's footprint has recently shrunk in Mosul, located 225 miles northwest of Baghdad, but the Iraqi wing of the terror group remains focused on thwarting Iraq's government and security forces.

In Baghdad, a car bomb killed one passer-by and wounded 17 other people as an Iraqi army convoy drove by al-Mustansiriya University in a Shiite neighborhood.

A Baghdad policeman said 11 soldiers were among the wounded. Cars parked along the street were also damaged in Thursday's explosion. The casualties were confirmed by a medic at nearby al-Kindi hospital.